Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reconciliation of Federal Statutory to Actual Tax Expense:
Federal statutory income tax rate	35.00%	35.00%	35.00%	35.00%
Federal statutory income tax at 35%	$ 9,985	$ 8,268	$ 27,481	$ 25,359
Tax-exempt interest income	(2,198)	(1,949)	(6,328)	(5,116)
Basis difference on sale of insurance subsidiary				2,252
Stock compensation	6	8	19	26
Earnings on life insurance	(216)	(249)	(1,186)	(734)
Tax credits	(165)	(145)	(423)	(437)
Other	57	624	196	(103)
Actual Tax Expense	$ 7,469	$ 6,557	$ 19,759	$ 21,247
Effective Tax Rate	26.20%	27.80%	25.20%	29.30%